From a MAD game theoretic perspective that makes a lot of sense. To avoid non-essential use of nukes, only give policymakers the option of launching everything. Then they will only launch in extreme circumstances. Hopefully only circumstances where there are already missiles inbound.
This avoids the possibility of gradual nuclear escalation, which can be more easily miscalibrated.
This seems somewhat impractical, assuredly - plans would have been made in a dark drawer for the case that an earstwhile allied country became politically unstable.
On both sides of the wall - it would have been feasible for a country to attempt to establish it's own alignment separate from the superpowers through the use of nuclear weapons
This avoids the possibility of gradual nuclear escalation, which can be more easily miscalibrated.